Studies on the growth, in culture, of two forms of Porphyra lacerata from Japan

Abstract

Comparative studies were conducted on two forms of Porphyra lacerata Miura (Bangiales, Rhodophyta). Growth, morphological characteristics and maturation were compared in small epiphytic forms collected from Banda, Chiba Prefecture and large epilithic forms from Enoshima, Kanagawa Prefecture. Germlings of both types were cultured at temperatures of 10, 15 and 20 °C, an irradiance of 40 μmol m-2 s-1 and photoperiods of 14L:10D (light:dark) and 10L:14D. After 12 weeks, under identical culture conditions, the maximum size of foliose thalli of the epiphytic form was less than the epilithic form. At a temperature of 10 °C, the morphology of the Enoshima plants changed from cordate to lanceolate, whereas those from Banda retained their cordate shape. Under various culture conditions, the formation and liberation of archeospores were more abundant in the form from Banda. These observations suggest that the two forms of P. lacerata may represent different species, but further studies are required.